Charge forming method and apparatus with overspeed governor

ABSTRACT

The invention disclosed embraces a charge forming method of and apparatus embodying an instrumentality responsive to engine vibrations or disturbances brought into operation when the engine reaches a predetermined speed to automatically deliver excess fuel to the engine thereby momentarily providing a nonignitible mixture preventing overspeeding of the engine.

United States Patent 1191 Nutten et a1. July 9, 1974 1 CHARGE FORMINGMETHOD AND [56] References Cited APPARATUS WFTH OVERSPEED UNITED STATESPATENTS GOVERNOR 1,828,650 10/1931 Duer 123/97 [75] Inventors; Warren D,Nutten, Grafton, Wig; 3,521,652 7/1970 Reeks i 1 123/198 BernardPhillips, Toledo, Ohi 3,601,102 8/1971 Schneider 123/97 [73] Assignee:Borg-Warner Corporation, Chicago, FOREIGN PATENTS OR APPLICATIONS 111.212,651 4/1965 Sweden 123/106 2 F d: 1, l 72 [2 1 118 Nov 9 PrimaryEranziner-Jnurence M. Goodrldge 1 1 PP 302,902 AssistantE\'an1inerRonald B. Cox

Related US Application Data Attorney, Agent, or FirmHarry O. Ernsberger[62] Division of Ser, No. 74,812, Sept. 23, 1970, which is a division ofSet. No. 766,580, Oct. 10, 1968, ABSTRACT abandoned- The inventiondisclosed embraces a charge forming method of and apparatus embodying aninstrumental- [52] 123/114 123/100, 123/101, ity responsive to enginevibrations or disturbances 123/1 1 1, 123/127, 123/1 14, 1 brought intooperation when the engine reaches a pre- [51] P Fozd 13/001 F021 13/061605d 13/04 determined speed to automatically deliver excess fuel [58]Fleld 0f Search 123/100, 97, 101, 119, to the engine thereby momentarilyproviding a nonig 123/1 14, 1 l 1, 1 15; 137/45, 6 8 nitible mixturepreventing overspeeding of the engine.

8 Claims, 76 Drawing Figures fPAIENTEB- 91914 3.822.685

sum 03 w PATENTEDJIR 91914 $822585 PATENTEBJUL 91m a m! @LEHEI Thisapplication is a division of my copending application Ser. No. 74,812,filed Sept. 23, 1970, which is a division of application Ser. No.766,580, filed Oct. 10, 1968 and now abandoned.

The invention relates to a method of and apparatus for controllingdelivery of fuel and air mixture to an intemal combustion engine tonormally supply a power mixture for engine operation under loadconditions and to automatically modify the mixture at predeterminedengine speed to govern the engine and prevent excessive high speed.

lnternal combustion engines of the reciprocating piston type andparticularly two cycle engines are used extensively for powering tools,such as chain saws, and for other uses where the engine is periodicallysubjected to high loads. When the load is suddenly reduced or removed,overspeeding of the engine results if the throttle remains in full openposition. One of the most important uses of small two cycle engineswhere such overspeeding of the engine is encountered is that ofoperating chain saws. ln the felling of trees or cutting of logs andtree limbs by the use of an engine driven chain saw, the saw issubjected to intermittent loading. When cutting a log or limb, the loadon the engine endures until the log or limb is severed. When the saw cutis completed, the saw breaks through and the engine, being momentarilyunloaded, attains an excessively high speed within a fraction of asecond after the load is removed. Overspeeding of a small engine,particularly an engine of the two cycle type, may result in severedamage to the engine for several reasons. As the lubricant for atwo-cycle engine is contained in the liquid fuel there may beinsufficient lubrication at excessive high speed. The components of theengine subjected to excessive high speed may be broken or fractured bycentrifugal forces. As running friction is greatly increased at highengine speeds, piston or bearing seizure may ensue rendering the engineinoperable.

If the operator does not instantly reduce the speed of the engine bymanipulation of the throttle when a no load condition occurs, enginedamage is liable to ensue. Chain saw operators, in trimming limbs from afelled tree are prone to walk along the tree trunk cutting off the limbssuccessively while holding the throttle continuously in wide openposition causing severe overspeeding of the engine between the limbcutting operations, a practice which usually results in damage to theengine. Such conditions of operation greatly reduce engine life andsubject the saw manufacturer to excessive warranty claims. The samedifficulties are encountered in other uses of internal combustionengines where the engine is subjected to overspeeding under no loadconditions.

The invention embraces a method of preventing excessive high speed of aninternal combustion engine by automatically modifying the fuel and airratio of the fuel and air mixture when. the engine exceeds apredetermined speed, the modification or change in fuel to air ratiobeing effected through a medium or means responsive to engine vibrationsor disturbances independently of the aspiration or reduced pressureexistent in the charge forming apparatus or carburetor providing thenormal fuel and air mixture.

Another object of the invention resides in a method of governing theoperation of an internal combustion engine, the method involving theautomatic delivery of an excess amount of liquid fuel to the enginewhenever the engine attains a predetermined speed, the delivery ofexcess fuel being controlled by a vibration responsive instrumentality.

Another object of the invention resides in amethod of governing orlimiting the speed of an internal combustion engine to preventoverspeeding of the engine involving a medium responsive to enginevibration occurring at a predetermined engine speed effective tosuperimpose excess liquid fuel on the normal fuel and air mixturesupplied to an engine to effect an impaired or slow burning mixtureresulting in an instantaneous decrease in the power of the engine andhence a substantial reduction in engine speed.

Another object of the invention resides in a method of governing thespeed of an internal combustion engine involving the automatic deliveryof an excess of liquid fuel into any region of the induction systemthrough the use of an instrumentality responsive to a predeterminedfrequency of vibration of the engine.

Another object of the invention resides in an apparatus or deviceactivated by or rendered out of phase with engine vibration ofpredetermined frequency to thereby deliver an excess of fuel into theinduction system operative to reduce the engine speed.

Still another object of the invention is the provision in the inductionsystem of an internal combustion engine of a vibration responsive valverendered effective at a predetermined frequency to admit an excess ofliquid fuel into the induction system or charge forming device tothereby reduce engine speed.

Another object of the invention is the provision of a vibrationresponsive valve associated with the induction system or charge fomiingapparatus for an internal combustion engine intercalated with fuelconveying passage means for delivering excess fuel to the engine at apredetermined frequency of vibration of the engine to preventoverspeeding thereof.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economies of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawing of a form of the invention, which may bepreferred, in which:

FIG. 1 is a side elevational view of a portion of a chain saw ofconventional construction illustrating the engine and a combineddiaphragm carburetor and fuel pump construction embodying a form of theinvention;

FIG. 2 is atop plan view of a combined diaphragm carburetor anddiaphragm fuel pump construction shown in FIG. 1 embodying a form of theinvention;

FIG. 3 is a side elevational view of the construction shown in FIG. 2;

FIG. 4 is an elevational view of the opposite side of 'the constructionshown in FIG. 2;

FIG. 5 is a view of the air inlet end of the carburetor and fuel pumpconstruction shown in FIG. 2;

FIG. 6 is a view of the mixture outlet end of the carburetor and fuelpump construction;

FIG. 7 is an enlarged longitudinal sectional view through the carburetorand fuel pump construction, the section line being taken substantiallyon the line 7-7 of FIG. 2;

FIG. 8 is an enlarged transverse sectional view taken substantially onthe line 8-8 of FIG. 7;

FIG. 9 is an enlarged fragmentary sectional view taken substantially onthe line 9-9 of FIG. 3;

FIG. 10 is an enlarged sectional view taken substantially on the lineIll-III of FIG. illustrating one form of overspeed governor meansembodied in the carbure tor;

FIG. 11 is an enlarged fragmentary sectional view taken substantially onthe line 11-11 of FIG. 4 illustrating the overspeed governor means shownin FIG.

FIG. 12 is a detail sectional view of a modified form of overspeedgovernor instrumentality;

FIG. I3 is a detail sectional view illustrating another form ofoverspeed governor instrumentality similar to that shown in FIG. 11;

FIG. 14 is an enlarged longitudinal sectional view of a charge formingapparatus or carburetor of the floatcontrolled type embodying a form ofoverspeed governor instrumentality of the invention;

FIG. 15 is an elevational view illustrating a reciprocating-pistoninternal combustion engine of the four cycle type illustrating a form ofoverspeed governor instrumentality of the invention associatedtherewith;

FIG. 16 is a top plan view of a portion of the carburetor or chargeforming apparatus of FIG. 15 illustrating the position of the overspeedgovernor means of the invention;

FIG. 17 is an enlarged fragmentary detail sectional view of a form ofoverspeed governor means of FIG. 15, the view being taken substantiallyon the line 17-17 of FIG. 15;

FIG. 18 is an end view of the construction shown in FIG. 17;

FIG. 19 is an elevational view of a two cycle engine associated with afloat type carburetor and embodying a form of overspeed governorinstrumentality of the invention;

FIG. 20 is an elevational view of a two cycle engine associated with adiaphragm type carburetor and embodying a form of overspeed governorinstrumentality of the invention;

FIG. 21 is a longitudinal sectional view of the diaphragm typecarburetor illustrated in FIG. 20;

FIG. 22 is an elevational view of a reciprocating piston four cycleengine equipped with a float-controlled type carburetor in combinationwith an engine-driven fuel pump and an overspeed governor means of thein-- vention associated with the mixture intake manifold;

FIG. 23 is a top plan view of the carburetor shown in FIG. 22 embodyingan overspeed engine governor instrumentality;

FIG. 24 is a view similar to FIG. 23 illustrating a fitting between thecarburetor and the intake manifold equipped with an overspeed governormeans of the invention;

FIG. 25 is a sectional view of a diaphragm type carburetor and fuel pumpconstruction similar to the form shown in FIG. 8 and embodying a form ofoverspeed engine governor means of the invention;

FIG. 26 is a top plan view of a diaphragm type carburetor and fuel pumpdisposed within an air filter enclosure, the arrangement embodying aform of overspeed governor of the invention;

FIG. 27 is an enlarged detail sectional view of a form of overspeedgovernor device embodied in the arrangement shown in FIG. 26;

FIG. 28 is a top plan view of a diaphragm type of charge formingapparatus or carburetor equipped with an overspeed governor means of theinvention;

FIG. 29' is a longitudinal sectional view through the carburetor, theview being taken substantially on the line 29-29 of FIG. 28;

FIG. 30 is a transverse sectional view taken substantially on the line30-30 of FIG. 28;

FIG. 31 is an enlarged fragmentary transverse sectional view takensubstantially on the line 31-31 of FIG. 28;

FIG. 32 is a view similar to FIG. 31 illustrating a form of capillaryseal arrangement for a main fuel delivery orifice associated with theoverspeed governor device of the invention;

FIG. 33 is a top plan view of a carburetor similar to FIG. 28 embodyinga modified form of overspeed governor device;

FIG. 34 is an enlarged detail sectional view taken substantially on theline 34-34 of FIG. 33;

FIG. 35 is a top plan view of a charge forming apparatus similar to FIG.33 embodying a form of overspeed governor means of the invention;

FIG. 36 is an enlarged detail sectional view taken substantially on theline 36-36 of FIG. 35;

FIG. 37 is a longitudinal sectional view through a carburetor similar toFIG. 10 illustrating a modified fuel channel arrangement for theoverspeed governor device;

FIG. 38 is an enlarged detail sectional view taken substantially on theline 38-38 of FIG. 37;

FIG. 39 is a top plan view of a diaphragm type carburetor embodying aform of overspeed governor of the invention;

FIG. 40 is a side elevational view of the construction shown in FIG. 39;

FIG. 41 is a horizontal sectional view taken substantially on the line41-41 of FIG. 40;

FIG. 42 is an enlarged detail sectional view taken substantially on theline 42-42 of FIG. 41; FIG. 43 is an enlarged detail sectional viewtaken substantially on the line 43-43 of FIG. 40;

FIG. 44 is an enlarged fragmentary sectional view similar to FIG. 42illustrating a capillary seal anti-back bleed means in the main fueldelivery orifice;

FIG. 45 is an enlarged sectional view illustrating a modified form ofoverspeed governor instrumentality;

FIG. 46 is an enlarged sectional view illustrating another modificationof overspeed governor means;

FIG. 47 is an end view of the construction of FIG. 46;

FIG. 48 is an enlarged sectional view illustrating another modified formof overspeed governor means;

FIG. 49 is a bottom plan view of a carburetor with the diaphragm removedshowing the fuel chamber, the car buretor being of the general charactershown in FIGS. 39 and 40 and embodying a further modification ofoverspeed governor means of the invention;

FIG. 50 is a sectional view taken substantially on the line 50-50 ofFIG. 49 illustrating the overspeed governor means;

FIG. 51 is an enlarged detailed sectional view illustrating anothermodified form of overspeed governor means;

FIG. 52 is an end view of the construction of FIG. 51;

line 5656 of FIG. 55;

FIG. 57 is an enlarged detail sectional view of the overspeed governorconstruction shown in FIGS. 55 and 56;

FIG. 58 is an end view of the construction shown in FIG. 57;

FIG. 59 is a sectional view of a closure member for the constructionshown in FIG. 57;

FIG. 60 is a view of the construction shown in FIG. 57 with a sealingmeans for sealing the adjustment in fixed position; 7

FIG. 61 is a view similar to FIG. 57 illustrating a modified form ofseat configuration for the vibration responsive ball valve;

FIG. 62 is an enlarged sectional view similar to FIG. 57 illustrating aclosure means for the adjustable member;

FIG. 63 is an end view of the construction shown in FIG. 62;

FIG. 64 is an enlarged sectional view illustrating a modified form ofadjustable overspeed governor construction;

FIG. 65 is an end view of the construction shown in FIG. 64;

FIG. 66 is a fragmentary sectional view of a portion of the constructionshown in FIG. 64 illustrating a sealing means for the adjustment;

FIG. 67 is an enlarged sectional view illustrating another form ofoverspeed governor construction of the invention;

FIG. 68 is an end view of the construction shown in FIG. 67;

FIG. 69 is an enlarged sectional view illustrating another form ofoverspeed governor construction;

FIG. 70 is an end view of the construction shown in FIG. 69;

FIG. 71 is an enlarged sectional view similar to FIG. 69 illustrating aclosure for the housing of the overspeed governor construction; v

FIG. 72 is an end view of the construction shown in FIG. 71;

FIG. 73 is an enlarged longitudinal sectional view illustrating anotherform of overspeed governor means;

FIG. 74 is an end view of the construction illustrated in FIG. 73;

FIG. 75 is a schematic sectional view of a reciprocating piston engineillustrating the relationship of the overspeed governor means shown inFIG. 73 with moving components of an engine for attaining overspeedgovernor operation, and

FIG. 76 is an enlarged sectional view of another modification of theoverspeed governor means of the invention. 1

The method and the apparatus of the invention involve feeding an excessof liquid fuel to a reciprocating piston internal combustion engine ofeither the two cycle or four cycle type through the use of a vibrationresponsive body actuated by or rendered out of phase with enginevibrations or disturbance occurring at a particular speed of the engineto cause oscillation or relative displacement of the body and therebyadmit fuel into the engine induction system in an amount effective toreduce the engine speed and prevent overspeed of the engine.

The apparatus for accomplishing this method is referred to hereingenerally as a vibration responsive in strumentality, means or unitproviding an overspeed governor, the governing medium being responsiveto and actuated or displaced by engine vibrations when the engineattains a predetermined speed. The overspeed governor method andarrangement of the invention have particular utility with low horsepowertwo and four cycle engines and especially engines employed for poweringchain saws, lawn mowers, portable drills and the like.

It is found that the vibration responsive means or valve may be arrangedto deliver liquid fuel into various regions of the induction system ofan engine and the drawings illustrate various arrangements forpositioning or mounting a vibration responsive body or valve whereby itis subjected to engine vibrations and is effective at a particularfrequency of vibration to be moved or oscillated by such vibration toadmit excess fuel to the engine for engine governing purposes.

Referring initially to FIG. I, there is illustrated a side elevationalview, partly in section, of a portion of the power driven chain sawshowing a form of charge forming apparatus or carburetor embodying theinvention associated with the engine. The arrangement shown in FIG. 1 isinclusive of a chain saw frame construction 10 which forms an integralpart of an engine crankcase ll of a two cycle engine 12 on which ismounted a cylinder 14 having cooling fins l5. Slidable in the cylinderI4 is a conventional piston 16 having a piston pin 17 connected by aconnecting rod 18 with a crank pin 19 on a crank arm of a crankshaft 20journally supported in the crankcase II.

The engine illustrated is of the two cycle type, viz. wherein the fueland air mixture is admitted into the chamber provided by the crankcaseI1 and compressed therein upon the down stroke of the piston 16, thecompressed mixture being then delivered through a suitable port into thecombustion chamber of the cylinder above the piston in the conventionalmanner. The mixture is ignited by a spark plug 22 at each revolution ofthe crankshaft.

The fuel and air combustible mixture is provided through a combined fuelpump and carburetor or charge forming apparatus 24 mounted by the enginecrankcase, the carburetor illustrated being shown in detail in FIGS. 2through 11 and hereinafter described.

The frame 10 is fashioned with a forwardly extending portion 34 to whichis secured an elongated plate-like member 35 providing a support andguide means for an endless chain type saw construction 36. The sawsupport plate 35 is secured to the frame by means of bolts 37. Theforward end of the support member 35 is provided with a housing 38 whichjournally supports a rol-

1. A method for governing the speed of an internal combustion enginewherein a combustible fuel and air mixture is provided for the engineincluding delivering fuel and air mixture from a charge forminginstrumentality to provide a normal combustible mixture for operatingthe engine, subjecting a vibrationresponsive fuel flow control sphericalbody normally closing a fuel passage to engine structural vibrationstransmitted through the engine frame, and effecting relative movement ofthe body laterally away from passage-closing position solely under theinfluence of engine structural vibrations of a frequency occurring at apredetermined engine speed to effect delivery of additional fuel throughthe fuel passage to the engine in an amount preventing an increase inthe speed of the engine.
 2. A method for governing the speed of areciprocating piston internal combustion engine wherein a combustiblefuel and air mixture is provided for the engine including deliveringfuel and air mixture from a charge forming instrumentality to the engineto provide a normal combustible mixture for operating the engine,subjecting a vibration-responsive fuel flow control valve body having aspherically-shaped valve surface to engine structural vibrations, andvibrating the body laterally away from a valve seat in a fuel passagesolely by engine structural vibrations transmitted through the engineframe occurring at a predetermined engine speed to deliver additionalfuel through the passage to the engine in an amount providing anoverrich mixture impairing engine operation thereby limiting the speedof the engine.
 3. A method for governing the speed of an internalcombustion engine wherein a combustible fuel and air mixture is providedfor the engine including delivering fuel and air mixture from a chargeforming instrumentality to the engine to provide a normal combustiblemixture for operating the engine, calibrating a relatively movable fuelflow control spherical body normally closing a fuel passage to be solelyresponsive to engine structural vibrations of a predetermined frequencytransmitted through the engine frame, biasing the spherical body topassage-closing position solely by spring pressure, and vibrating thespherical body by vibrations of the predetermined frequency to move thebody away from passage-closing position to effect flow of additionalfuel through the fuel passage past the body to the engine in an amounteffective to limit the speed of the engine.
 4. The meThod according toclaim 3 including the step of damping vibrations of the body occurringat the predetermined vibration frequency.
 5. The method of limiting thespeed of a two cycle internal combustion engine wherein fuel and airmixture is delivered to the engine crankcase by aspiration includingflowing air by engine aspiration through a mixing passage, aspiratingfuel from a supply into the air flowing through the mixing passage toprovide a combustible mixture for operating the engine, normallyimpeding fuel flow through a channel to the engine crankcase by avibration-responsive spherically-shaped body, biasing thespherically-shaped body solely by spring pressure to fuel-flow impedingposition, and vibrating the body solely by the frequency of enginestructural vibration transmitted through the engine frame occurring at apredetermined engine speed to effect vibratory movement of the body awayfrom fuel-flow impeding position to admit fuel through the channel in anamount sufficient to impair combustion in the engine and thereby limitthe speed of the engine.
 6. The method of limiting the speed of areciprocating-piston internal combustion engine wherein fuel and airmixture is delivered to the engine crankcase by aspiration includingflowing air by engine aspiration through a mixing passage, aspiratingfuel from a supply into the air flowing through the mixing passage toprovide a combustible mixture for operating the engine, normallyimpeding fuel flow through a channel for delivery to the engine by avibration-responsive body having a spherically curved surface, yieldablybiasing the vibration-responsive body solely by spring pressure toengage the spherically curved surface with a valve seat and impede fuelflow through the channel, said body being solely responsive to enginestructural vibration transmitted through the engine frame, anddisplacing the body from the valve seat at a frequency of enginestructural vibration occurring at a predetermined engine speed to admitfuel through the channel in an amount to impair combustion in the engineand thereby limit the speed of the engine.
 7. The method of limiting thespeed of a reciprocating-piston internal combustion engine wherein fueland air mixture is delivered to the engine by aspiration includingflowing air by engine aspiration through a mixing passage, aspiratingfuel from a supply into the air flowing through the mixing passage toprovide a combustible mixture for the engine, normally impeding flow ofadditional fuel through a channel opening into the mixing passage by aspherically-shaped vibration-responsive valve body, biasing the valvebody to fuel-flow impeding position solely by spring pressure, saidvalve body being solely responsive to engine structural vibrationtransmitted through the engine frame, and vibrating the valve body byengine structural vibration occurring at a predetermined engine speed toeffect relative movement of the body away from fuel-flow impedingposition to admit fuel through the channel in an amount sufficient toimpair combustion in the engine to thereby reduce the speed of theengine.
 8. The method of operating a reciprocating-piston internalcombustion engine having a fuel and air induction system, delivering acombustible fuel and air mixture to the induction system for operatingthe engine, normally impeding flow of additional fuel from a supply intothe system by a spherically-shaped valve body rendered relativelymovable under the influence of engine structural vibrations of apredetermined frequency, biasing the spherically-shaped valve body tofuel-flow impeding position solely by spring pressure, and displacingthe valve body solely by engine structural vibrations of thepredetermined frequency away from fuel-flow impeding position foradmitting additional fuel into the induction system from the supply inan amount effective to impair combustion and thereby limit the speed ofthe engine.